Japan
Pressure Dependence of CO2 Effect on Hydrogen-assisted Fatigue Crack Growth in Two Pipeline Steels
Oct 2024
Publication
This study investigated the pressure-dependent CO2 effect on the hydrogen embrittlement of X80 and GB20# pipeline steels by combining experiments and first-principles calculations. Results revealed that the CO2 effect enhanced the fatigue crack growth for GB20# steel in 10 MPa CO₂-enriched hydrogen mixtures. However the improved degree by the CO₂ effect at 10 MPa was less pronounced than at 0.4 MPa which was found for the first time. This was attributed to the decreased adsorption rate of CO₂ on iron as hydrogen pressure increased. Therefore in high-pressure CO₂-enriched hydrogen mixtures CO2 could not significantly accelerate the inherent rapid hydrogen uptake at high pressure.
Hydrogen Embrittlement Behaviors During SSRT Tests in Gaseous Hydrogen for Cold-word Type 316 Austenitic Stainless Steel and Iron-based Supperalloy A286 Used in Hydrogen Refueling Station
Feb 2024
Publication
To consider an appropriate evaluation method for hydrogen compatibility slow strain rate tensile (SSRT) tests were conducted on high strength piping materials cold-worked type 316 austenitic stainless steel (SUS316CW) and iron-based superalloy A286 used in hydrogen stations for two years.<br/>SUS316CW used at room temperature in 82 MPa gaseous hydrogen contained 7.8 mass ppm hydrogen. The SSRT test of SUS316CW was conducted in nitrogen at -40 °C. The fracture surface showed dimples and no hydrogen embrittlement behavior was observed. While the SSRT test of SUS316CW in 70 MPa gaseous hydrogen at -40 °C showed a slight decrease in reduction area and a brittle fracture morphology in the outer layer. This was considered to be the effect of high-pressure gaseous hydrogen during the SSRT test in addition to the pre-contained hydrogen.<br/>A286 used at -40 °C in 82 MPa gaseous hydrogen contained negligible hydrogen (0.14 mass ppm). SSRT tests were conducted at 150 °C in 70 MPa gaseous hydrogen and in air and showed a low relative reduction in area (RRA) value. To investigate the decrease in the RRA we switched the gas from hydrogen to air in the middle of the SSRT test and closely examined the RRA values and fracture morphology including side cracks. The hydrogen embrittlement was found to originate from the elastic deformation region. Stress cycling in the elastic deformation region also accelerated the effect of hydrogen. These were attributed to an increase in the lattice hydrogen content. While in the plastic deformation region hydrogen trapped in the defects and hydrogen through the generated surface cracks increased the hydrogen content at the crack tips reducing the RRA value. And there was a good correlation between the crack lengths and RRA values.<br/>Then hydrogen embrittlement mechanism depends on the operating conditions (stress and temperature) of the material and evaluating the hydrogen compatibility of materials by controlling their hydrogen content and strain according to the service environment is desirable.
Exploring Decarbonization Priorities for Sustainable Shipping: A Natural Language Processing-based Experiment
Oct 2024
Publication
The shipping industry is currently the sixth largest contributor to global emissions responsible for one billion tons of greenhouse gas emissions. Urgent action is needed to achieve carbon neutrality in the shipping industry for sustainability. In this paper we use natural language processing techniques to analyze policies announcements and position papers from national and international organizations related to the decarbonization of shipping. In particular we perform the analysis using a novel matrix-based corpus and a fine-tuned machine learning model BERTopic. Our research suggests that the top four priorities for decarbonizing shipping are preventing emissions from methane leaks promoting non-carbon-based hydrogen implementing reusable modular containers to reduce packaging waste in container shipping and protecting Arctic biodiversity while promoting the Arctic shipping route to reduce costs. Our study highlights the validity of NLP techniques in quantitatively extracting critical information related to the decarbonization of the shipping industry.
Integrated Home Energy Management with Hybrid Backup Storage and Vehicle-to-Home Systems for Enhanced Resilience, Efficiency, and Energy Independence in Green Buildings
Sep 2024
Publication
This study presents an innovative home energy management system (HEMS) that incorporates PV WTs and hybrid backup storage systems including a hydrogen storage system (HSS) a battery energy storage system (BESS) and electric vehicles (EVs) with vehicle-to-home (V2H) technology. The research conducted in Liaoning Province China evaluates the performance of the HEMS under various demand response (DR) scenarios aiming to enhance resilience efficiency and energy independence in green buildings. Four DR scenarios were analyzed: No DR 20% DR 30% DR and 40% DR. The findings indicate that implementing DR programs significantly reduces peak load and operating costs. The 40% DR scenario achieved the lowest cumulative operating cost of $749.09 reflecting a 2.34% reduction compared with the $767.07 cost in the No DR scenario. The integration of backup systems particularly batteries and fuel cells (FCs) effectively managed energy supply ensuring continuous power availability. The system maintained a low loss of power supply probability (LPSP) indicating high reliability. Advanced optimization techniques particularly the reptile search algorithm (RSA) are crucial in enhancing system performance and efficiency. These results underscore the potential of hybrid backup storage systems with V2H technology to enhance energy independence and sustainability in residential energy management.
Analysis of Hydrogen Value Chain Events: Implications for Hydrogen Refueling Stations’ Safety
Apr 2024
Publication
Renewable hydrogen is emerging as the key to a sustainable energy transition with multiple applications and uses. In the field of transport in addition to fuel cell vehicles it is necessary to develop an extensive network of hydrogen refueling stations (hereafter HRSs). The characteristics and properties of hydrogen make ensuring the safe operation of these facilities a crucial element for their successful deployment and implementation. This paper shows the outcomes of an analysis of hydrogen incidents and accidents considering their potential application to HRSs. For this purpose the HIAD 2.0 was reviewed and a total of 224 events that could be repeated in any of the major industrial processes related to hydrogen refueling stations were analyzed. This analysis was carried out using a mixed methodology of quantitative and qualitative techniques considering the following hydrogen value chain: production storage delivery and industrial use. The results provide general information segmented by event frequency damage classes and failure typology. The analysis shows the main processes of the value chain allow the identification of key aspects for the safety management of refueling facilities.
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